Free PX to REM & VW converter

A fast, no-nonsense pixel calculator for responsive web design. Type a value in pixels — or tap a preset — and instantly get it in rem (relative to a 16px root) or in vw, relative to any viewport width. Round the result to the precision you need and copy it straight into your CSS. Everything runs in your browser, with nothing to install.
Pixel Converter
Pixels to rem & vw
1.6667vw
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Why convert pixels?

Designers hand off layouts in pixels, but responsive, accessible CSS is built on relative units. Converting your pixel values to rem keeps typography and spacing scalable and respectful of the user's browser settings, while vw lets elements grow and shrink fluidly with the viewport. This converter removes the mental math so you can move from a Figma spec to production CSS in seconds.

What are rem and vw?

  • rem — "root em." One rem equals the font size of the root <html> element, which is 16px by default. So 24px ÷ 16 = 1.5rem. Size in rem and everything scales cleanly when a user changes their base font size.
  • vw — "viewport width." One vw equals 1% of the viewport's width. On a 1440px-wide screen, 24px ÷ 1440 × 100 = 1.6667vw. Use it for fluid, full-width layouts that respond to screen size.

Features

  • Two modes — switch between PX → REM and PX → VW with a single tap.
  • Quick presets — a row of common pixel steps around your current value; tap to jump.
  • Adjustable rounding — trim the decimals one at a time until the number is exactly as tidy as you want.
  • One-click copy — grab the result, unit included, ready to paste into CSS.
  • 100% private & instant — it all happens locally in your browser; nothing is uploaded.

How to use it

  1. Pick a mode — PX → REM or PX → VW.
  2. Type a pixel value, or tap one of the presets above the field.
  3. In VW mode, set the viewport width to match your design.
  4. Tap "Round it" to shave off decimals until it's clean.
  5. Copy the result and drop it into your stylesheet.

Loved by web people

"Exactly the tiny utility I keep open in a tab all day. Paste a pixel value, get clean rem, copy, done."
—  Maya R. · Front-end developer
"The vw mode with a custom viewport width is what sold me — fluid type calculations without spinning up a calculator."
—  Daniel K. · UI engineer
"The round-it button is a lovely touch. I get exactly the precision I want and nothing more."
—  Priya S. · Design systems lead

Frequently asked questions

How do I convert px to rem?

Divide the pixel value by the root font size (16px by default). For example, 24px ÷ 16 = 1.5rem — this tool does it instantly.

How do I convert px to vw?

Divide the pixel value by the viewport width and multiply by 100. On a 1440px viewport, 24px becomes 1.6667vw.

Which viewport width should I convert against?

Use the width your design was created at — commonly 1440px, 1920px, or 375px for mobile. Set it in the field and the vw result updates instantly.

Is this converter free?

Yes — completely free, no sign-up, and it runs entirely in your browser.